Heterocoagulate, and compositions and method for polishing and surface treatment

ABSTRACT

A heterocoagulate comprises first particles, having a particle size of at most 999 nm, on a second particle, having a particle size of at least 3 microns. The first particles comprise cerium oxide, and second particle comprises at least one member selected from the group consisting of silicon oxides, aluminum oxides and zirconium oxides.

BACKGROUND

The polishing of glass using cerium oxide (ceria) is well establishedand has a long history of use (see, for example, U.S. Pat. No. 2,383,500and U.S. Pat. No. 2,816,824). Not only has ceria been used to shapeglass into lenses, but it can also be used to polish the surface of theglass to chemically prepare it for the application of surface treatments(see, for example, Bartrug et al., U.S. Pat. No. 6,025,025 and Iversenet al., Patent Application Publication Pub. No. US 2009/0075093). Inaddition, ceria has been used to polish a variety of other silicon oxidesurfaces both chemically and mechanically, for example photomask blanks,lithography optics and silicon wafers.

For final stage polishing applications, available ceria slurriestypically have particle sizes small enough that they do not producevisible scratches. Particularly for high-performance applications, theparticles are dispersed down to their primary size, do not containhigher-order agglomerates, and the dispersion of particles are stable(see, for example, P. G. Murray, “Nanocrystalline Cerium Oxide ImprovesGlass Polishing Operations” Photonics Spectra, August 2004). Examples ofsuch high-performance ceria slurries include cerium oxide dispersions ofNanoArc® Cerium Oxide nanopowder (Nanophase Technologies Corporation,Romeoville, Ill.; crystalline, non-porous, non-agglomerated particleshaving a mean particle size of 30 nm), such as NanoTek® CE-6040. Theparticles in the dispersion have a high zeta potential of 35-45 mV inthe pH range of 3-4, and they form stable dispersions in water withoutadditives (see, for example, Sarkas et al., U.S. Pat. No. 7,517,513).

Hydrophilic surface treatment of glass and other hard surfaces usingsilica sols is well established (see, for example, JP 01014129, issued 8Jun. 1987, and Bindzil® CC product Brochure published by Eka/Akzo Nobel,April 2008). Not wishing to be bound by any particular theory, silicaparticles are present in a basic solution containing a volatile base,such as ammonia; as water, solvent and/or base evaporates, the silicaparticles coalesce and form a fully hydrated silicon oxide surface. Thesurface is very hydrophilic, and may be self-cleaning with ambientwater, such as rain, which wets the surface and may remove dust anddirt. The use of silica and silicate hydrophilic surface treatments isadvantageous in that no photoactivation is required in order achieve ahydrophilic effect, in contrast to analogous treatments based ontitanium dioxide or titanium-substituted hydroxyapatite. In addition, ahigh degree of optical clarity is readily achieved using either silicaor silicates, since these materials possess refractive indices veryclose to those of typical glass substrates, in contrast to titaniumdioxide or titanium-substituted hydroxyapatite.

Stains on glass, particularly architectural glass, for example windowglass in buildings, ships, and homes, are preferably removed beforeapplying a surface treatment to the glass. The stains are often referredto as mineral or hard water stains. Compositions for removing mineralstains or hard water stains typically contain an abrasive and/or acid(see, for example, U.S. Pat. No. 3,425,870, U.S. Pat. No. 3,573,886 andU.S. Pat. No. 4,102,706). The acid present in some of these compositionsincludes mineral acids (such as hydrofluoric acid and hydrochloric acid)and/or organic acids.

SUMMARY

In a first aspect, the present invention is a heterocoagulate,comprising (a) first particles, having a particle size of at most 999nm, comprising cerium oxide, on (b) a second particle, having a particlesize of at least 3 microns, comprising at least one member selected fromthe group consisting of silicon oxides, aluminum oxides and zirconiumoxides.

In a second aspect, the present invention is a polishing composition,comprising (1) a plurality of heterocoagulates, each heterocoagulatecomprising (a) first particles, having a particle size of at most 999nm, comprising cerium oxide, on (b) a second particle, having a particlesize of at least 3 microns, comprising at least one member selected fromthe group consisting of silicon oxides, aluminum oxides and zirconiumoxides. The polishing composition also comprises (2) water, and (3) anorganic acid. The composition has a pH of at most 6.

In a third aspect, the present invention is a method of treating asurface of a substrate, comprising polishing the substrate with thepolishing composition, to produce a polished surface of the substrate. Asurface treatment composition may be applied on the polished surface, toproduce a treated surface.

In a fourth aspect, the present invention is a kit, comprising thepolishing composition, in a first container, and a surface treatmentcomposition, in a second container.

DEFINITIONS

The term “heterocoagulate” means a composite structure of a plurality offirst particles (typically nanopartices) on the surface of a secondparticle (typically a microparticle). The first particles are in contactwith the second particle, and the first particles are present asindividual particles (in addition, some of the first particles may alsobe present in small groups). An example of a heterocoagulate is shown inFIG. 1, where two first particles on two separate second particles, areidentified as cerium oxide particles. This is in contrast to thecomposite particle shown in FIG. 2, where the first particles are onlypresent in aggregates, one of which is identified as cerium oxideaggregate, therefore most first particles are not in contact with thesecond particle. Typically, in a hetercoagulate, the first particles aremaintained on the surface of the second particle by electrostaticforces. In a heterocoagulate, aggregates of the first particles,containing at least 200 first particles, are preferably not present onthe second particle.

The term “nanoparticle” means a particle having a particle size of atmost 999 nm. Preferably, a nanoparticle has a particle size of 10 nm to500 nm.

The term “microparticle” means a particle having a particle size of atleast 1 micron (1000 nm). Preferably, a microparticle has a particlesize of 2 microns to 500 microns.

The term “particle size” means the average diameter of the image of theparticle as viewed by electron microscopy, unless otherwise stated. Theterm “average particle size” means the average of the particle sizes ofa collection of particles.

The term “polishing” means rubbing the surface, for example “polishingthe widow with a polishing composition” would be rubbing the surface ofthe window with a composition intended for rubbing a surface. Thesurface rubbed would be referred to the “polished surface”, for examplepolishing a window will result in a polished surface of the window.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electron micrograph of a heterocoagulate of first particlesof cerium oxide on a second particle of pumice.

FIG. 2 is an electron micrograph of a composite particle (not aheterocoagulate) of aggregated ceria particles on an alumina particle.

DETAILED DESCRIPTION

Providing a hydrophilic surface on glass, such as windows, improves theability of ambient water, such as rain, to remove dirt or dust, creatinga self-cleaning surface. A hydrophilic surface on glass may be createdusing a two-part treatment: first polishing the glass with a colloidalsuspension of ceria, followed by treating the polished surface with asilica sol. Prior to creating this hydrophilic surface, it would bedesirable to remove any stains, such as mineral stains. Many effectivestain removal compositions contain an organic acid. In an effort tocombine the first two of these three stages, (1) stain removal and (2)polishing, it was discovered that the colloidal suspensions of ceriaflocculate in the presence of an organic acid, degrading the ability ofthe polishing composition to activate the surface of the glass. Withoutwishing to be bound by any particular theory, it is believed that theorganic acids associate with the surfaces of the ceria particles therebydisrupting colloidal stability, which leads to agglomerate and aggregateformation. Furthermore, colloidal suspensions of ceria, without organicacid, do not efficiently remove mineral or hard water stains.

The present invention makes use of the discovery that ceria particleswill form a heterocoagulate with particles of pumice (aluminumsilicate). Surprisingly, the heterocoagulate is effective for polishingglass, similar to a dispersion of the ceria particles; however, theeffectiveness of the heterocoagulate is not significantly altered whenan organic acid is present. In the heterocoagulate, the ceria particlesare present as individual particles on the surface of the second(pumice) particle (FIG. 1). In contrast, if a composite particle isformed which has only aggregated ceria particles on the surface of thesecond particle (FIG. 2), the composite particle is less effective forpolishing the glass, compared to the heterocoagulate. When prepared asan aqueous polishing composition, which contains an organic acid, andthe heterocoagulate of ceria particles and a pumice particle, thecombination provides a single composition for both removing stains fromglass, and polishing the glass. Polishing a substrate with the polishingcomposition can remove stains and activate the surface; treating thepolished surface with a surface treatment, will then provide a treatedsurface, such as a hydrophilic surface if the surface treatmentcomposition contains an appropriate silica sol.

A polishing composition contains a heterocoagulate, water, and anorganic acid. The heterocoagulate is composed of smaller first particlescontaining a cerium oxide, such as nanoparticles of ceria, on a secondparticle containing a silicon oxide, an aluminum oxide, a zirconiumoxide, or combinations thereof, such as a microparticle of pumice.Preferably, the composition is buffered, so that it maintains an acidpH, preferably a pH of 6 or less, during polishing. Optionally, thecomposition also contains a surfactant, a thickener, a solvent, aprocessing aid, fragrance, and/or colorants, and any permutation orcombinations thereof.

The first particles contain a cerium oxide, such as ceria, mischmetaloxide, La/Ce oxides, as well as complex oxides of cerium and othermetals, such as zirconium-cerium oxides and mixed zirconium-rare earthoxides containing cerium. Preferably, the first particles contain ceria.Preferably, the first particles are nanoparticles having a particle sizeof at most 999 nm, including a particle size of at most 100, 200 and 500nm, more preferably a particle size of 10 nm to 500 nm, most preferablya particle size of 15 nm to 250 nm, such as 20, 30, 40, 50, 60, 70, 80,90 and 100 nm. Preferably, the first particles have an average particlesize of at most 999 nm, including an average particle size of at most100, 200 and 500 nm, more preferably an average particle size of 10 nmto 500 nm, most preferably an average particle size of 15 nm to 250 nm,such as 20, 30, 40, 50, 60, 70, 80, 90 and 100 nm. Preferably, the firstparticles have a large zeta potential in water at a pH of 3-4, forexample a zeta potential of 35-45 mV. An example of first particles arestoichiometric-nanostructured materials of cerium oxide prepared asdescribed in Sarkas et al., U.S. Pat. No. 7,517,513, available fromNanophase Technologies Corporation, under the names NanoArc® CeriumOxide nanopaticles, and CE-6040 dispersions (25% cerium oxide in water).Preferably, the first particles are present in an amount of 0.1 to 10%by weight, more preferably 1 to 8% by weight, such as 2 to 5% by weight,including 2.5, 3, 3.5, 4 and 4.5% by weight.

The second particle contains silicon oxide, aluminum oxide and/orzirconium oxide, as well as mixtures and combinations thereof. Examplesof silicon oxides include silica, aluminosilicates (including amorphousaluminosilicate, crystalline aluminosilicates, and pumice) and othersilicates. Examples of aluminum oxides include alumina, aluminosilicates(including amorphous aluminosilicate, crystalline aluminosilicates, andpumice) and magnesium aluminum oxides (for example, spinel). Examples ofzirconium oxides include zirconia (for example, yttrium-stabilized cubiczirconia), zirconium-cerium oxide, aluminum-zirconium oxide, zirconiumsilicate (zircon) and mixed zirconium-rare earth oxides. Preferably, thesecond particle comprises an aluminosilicate, for example pumice.Preferably, the second particle is a microparticle having a particlesize of at least 3 microns, for example a particle size of 3 to 500microns, including a particle size of 3 to 250 microns, and a particlesize of 10 to 100 microns, including 20, 30, 40, 50, 60, 70, 80 and 90microns. The average particle size of the second particles in thecomposition may be 3 to 500 microns, 3 to 250 microns, or 10 to 100microns, including an average particle size of 20, 30, 40, 50, 60, 70,80 and 90 microns. Examples include second particles having an averageparticle size of 3 to 100 microns, with no particles having a particlesize greater than 250 microns, or with no particles having a particlesize greater than 100 microns. Examples include particles of grade F,FF, FFF, FFFF, −325/F, −200/F and corresponding FEPA grit. Preferably,the second particles are present in an amount of 10 to 70% by weight,more preferably 30 to 60% by weight, such as 35 to 45% by weight,including 36, 37, 38, 39, 40, 41, 42, 43 and 45% by weight.

When present together, particularly in water or an aqueous solution, thefirst particles and the second particle will preferably form aheterocoagulate. The first particles are preferably present as adispersion, in water or an aqueous solution, when mixed with the secondparticle. Other ingredients of the polishing composition may be addedbefore, during or after the first particles and the second particle aremixed together, however, the first particles should not be allowed toaggregate together before introducing the second particle, or aheterocoagulate may not form. This can usually be avoided by mixing thefirst particles and the second particle together before adding otheringredient, or quickly after adding other ingredients. The organic acidmay cause the first particles to aggregate if mixed with a dispersion ofthe first particles, without quickly adding the second particle.

The organic acid may be chosen from any organic acid. Examples includeacetic acid, citric acid, glycolic acid, gluconic acid, lactic acid,oxalic acid, sulfonic acid, tartaric acid, trifluoroacetic acid, acidicorganic polymers, and mixtures thereof, preferably in combination, suchas a combination of citric acid, glycolic acid, and oxalic acid, oroxalic acid, tartaric acid, and trifluoroacetic acid. The organic acidmay be present with the corresponding conjugate base, to provide abuffer, which will resist changes in pH during polishing. Furthermore, abuffer, such as a phosphate buffer containing a phosphoric acid or anyof its conjugate bases, may be added in addition to the organic acid.Other acids may also be added in addition to the organic acid, includingother organic acids and one or more mineral acids (for example sulfuricacid, nitric acid, hydrochloric acid, hydrofluoric acid, and mixturesthereof). Preferably, the pH of the composition is less than 5, lessthan 4, less than 3, or less than 2, including a pH of 0.5 to 5, 1 to 4,or 3 to 4. Preferably, the organic acids are present in an amount of 1to 25% by weight, more preferably 2 to 20% by weight, such as 3 to 15%by weight including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14%. Whencombinations of organic acids are used, each is preferably present in anamount of 1 to 4% by weight, including 1.5, 2, 2.5, 3 and 3.5% byweight.

Optionally, a surfactant is included in the polishing composition. Oneor more surfactants may be used, for example ionic surfactants such asalkyl sulfates (for example, sodium lauryl sulfate), alkyl ethersulfates (for example, sodium laureth sulfate) and alkyl benzenesulfonates (for example, dodecylbenzene sulfonic acid and sodiumdodecylbenzene sulfonate), alkyl sulfosuccinates (for example sodiumdioctyl sulfosuccinate); and non-ionic surfactants such as alcoholethoxylates (for example, nonylphenol ethoxylates, octylphenolethoxylates, secondary alcohol ethoxylates, and branched alcoholethoxylates), alkyl polyglucosides, and ethylene oxide/propylene oxidecopolymers; and mixtures thereof. Preferably, the surfactant is presentin an amount of 0.1 to 10% by weight, more preferably 0.2 to 5% byweight, such as 0.3 to 3% by weight, including 0.4, 0.5, 0.6, 0.7, 0.8,0.9, 1, 1.5, 2 and 2.5% by weight.

Optionally, a thickener is included in the polishing composition. One ormore thickeners may be used, for example clays such as hectorite clays,garamite clays, organo-modified clays; saccharides and polysaccharidessuch as xanthan gum; celluloses and modified celluloses such ascarboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropylcellulose; acrylate and (meth)acrylate polymers and copolymers; andmodified ureas such as BYK® 420 (available from BYK Chemie). Examplesinclude OPTIFLO® H400, H500, H600, HV80; Optigel® WX, CG, WH; Laponite®RD and Laponite® B, from Southern Clay Products. Other viscositymodifiers may be used, as well as particle addition to controlviscosity, as described in Lewis et al., Patent Application PublicationPub. No. US 2003/0091647.

Optionally, a solvent is included in the polishing composition. One ormore solvents may be used, for example methoxyethanol, ethoxyethanol,propoxyethanol and butoxyethanol; glycols and glycol ethers such asdipropylene glycol methyl ether and dipropylene glycol ethyl ether;pyrrolidones such as methylpyrrolidone and ethyl pyrrolidone.Preferably, the solvent is present in an amount of 0.1 to 20% by weight,more preferably 1 to 15% by weight, such as 2 to 10% by weight,including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14% by weight.

Optionally, a processing aid is included in the polishing composition,such as one or more defoamers. Typical defoamer compositions useful inthe present invention include mixtures of polyethersiloxanes withorganic polymers and fumed silica, modified polyether-polysiloxanecopolymers and fumed silica, or molecular defoamers such as3,5-dimethyl-1-hexyn-3-ol. Examples include TEGO® Foamex 800, 805, 808,810, 815N, 822, 825, 830, 832, 835, 840, 842, 843, 855, 1488, 1495,3062, 7447, 8030 and 8050, from Evonik. Optionally, one or morefragrances, and/or colorants or dyes may also be included in thepolishing composition.

Surfactants, thickeners, solvents and processing aids should be selectedto avoid interfering with the chemical and mechanical properties of thecomposition. Not wishing to be bound by any particular theory, it isthought that these agents may disrupt the chemical polishing action ofthe first particles of the heterocoagulate. This has been observed forselected defoamers, particularly acetylenic-modified, polysiloxane-basedemulsion defoamers, selected thickeners, particularly inverse emulsionthickeners based on acrylamide copolymers, and with selected cellulosicand polysaccharide thickeners when used at excessive levels.

A water sheeting test may be used to identify those agents which maydisrupt the chemical polishing action of the first particles. This watersheeting tests is performed by polishing the surface of a glass sheet,and then running water over the entire polished surface while observingthe behavior of the water. If the water forms a continuous thin filmthat uniformly wets the surface, then the composition meets the watersheeting test and the agent or agents added do not disrupt the chemicalpolishing action. Pooling, where the water partially pulls away from theglass in isolated streams, or beading, where the water completely pullsaway from the glass surface in isolated beads, indicates that thecomposition does not meet the water sheeting test, and disruption of thechemical polishing action may be occurring.

Optionally, a surface treatment composition is applied to the polishedsurface, to produce a treated surface. The surface treatment compositionpreferably contains water, nanoparticles with an average diameter below100 nm, a surface wetting agent, a compound used for pH adjustment, anda pH indicator. Preferably, the nanoparticles contain silica or asynthetic hectorite clay, such as Laponite RD (Southern Clay Products, aparticulate material having a tabular platelet structure with a typicaldiameter of 25 nm and a plate thickness of 1 nm). Such a surfacetreatment composition may be used to produce a hydrophilic surface.Other surface treatments may be used, for example surface treatmentsthat provide a hydrophobic surface, a reflective surface and/or ascratch resistant surface.

A preferred surface treatment composition includes nanoparticles with anparticle size of at most 100 nm, or at most 30 nm, for example aparticle size of 5 to 100 nm, including a particles size of 10 to 50 nm,for example 11, 12, 15, 20, 25, 30, 35, 40 and 45 nm. Preferably, thenanoparticles have an average particle size of at most 100 nm, or atmost 30 nm, for example an average particle size of 5 to 100 nm,including an average particles size of 10 to 50 nm, such as 11, 12, 15,20, 25, 30, 35, 40 and 45 nm. Preferably, the nanoparticles are presentin an amount of 0.1 to 2.0% by weight, more preferably 0.2 to 1.5% byweight, such as 0.3 to 1.0% by weight, including 0.4, 0.5, 0.6, 0.7, 0.8and 0.9% by weight.

A preferred surface treatment composition includes one or more surfacewetting agents, such as methanol, ethanol, isopropanol, and mixtures ofalcohols. Optionally, a further wetting agent may be included, such asmethoxyethanol, ethoxyethanol, propoxyethanol and butoxyethanol, as wellas surfactants and dispersants, for example polyacids and/or silicones.The surface wetting agent may also be incorporated onto the nanoparticlethrough functionalization of the particle surface; for example, Bindzil®CC 30 supplied by Eka Chemical (an epoxy silane treated colloidalsilica).

A preferred surface treatment composition includes one or more compoundsused for pH adjustment, such as ammonia, alkyl amines, their salts, andmay also include buffers or acids. A preferred surface treatmentcomposition includes one or more pH indicators, such as phenolphthaleinor thymolphthalein. A preferred pH of the preferred surface treatmentcomposition is 10 to 11.

The polishing compositions of this disclosure may remove stains,especially mineral and hard water stains on windows. The polishingcomposition is also effective to activate a surface for subsequentlyforming a treated surface using a surface treatment composition. Thepolishing composition may also be effective to remove frosting on awindow due to the use of a stain removing composition that etches glass,such as hydrofluoric acid, or to remove scratches or other surfacedefects that may be present on the window.

A variety of surface treatments may be used. For windows, a surfacetreatment composition that forms a hydrophilic surface is preferred.

EXAMPLES Example 1

A polishing composition is described in the table below.

Material Supplier Function CE-6040 Nanophase Nanoparticle TechnologiesAbrasive Grade FFFF Pumice Hess Pumice Microparticle Base AbrasiveGlycolic Acid Solution DuPont Organic Acid 70 wt % Tech Solution CitricAcid Powder Jungbunzlauer Organic Acid Anhydrous USP Oxalic Acid PowderSamirian Organic Acid Sodium Dodecyl Sulfate Pilot Chemical Surfactant(Calfoam SLS-30 Solution (30 wt %)) Di (Propylene Glycol) Dow ChemicalSolvent Methyl Ether (Dowanol DPM) Defoamer¹ 0.003 Processing Aid BYK ®420 .02 Thickener (BYK Chemie) Fragrance 0.004 Fragrance Deionized water0.286 Main Liquid Phase ¹TEGO ® Foamex 810 is a proprietary mixture ofmodified polyether-polysiloxane copolymer and fumed silica from Evonik.

Example 2

A polishing composition is described in the table below. This polishingcomposition polishes more slowly than the composition of Example 1.

Material Supplier Function CE-6040 Nanophase Nanoparticle TechnologiesAbrasive Celatom FW14 Eagle Picher Microparticle Diatomaceous Earth¹Industies Base Abrasive Glycolic Acid Solution DuPont Organic Acid 70 wt% Tech Solution Citric Acid Powder Jungbunzlauer Organic Acid AnhydrousDSP Oxalic Acid Powder Samirian Organic Acid Sodium Dodecyl SulfatePilot Chemical Surfactant (Calfoam SLS-30 Solution (30 wt %)) Di(Propylene Glycol) Dow Chemical Solvent Methyl Ether (Dowanol DPM)Defoamer² 0.003 Processing Aid BYK ® 420 .02 Thickener Fragrance 0.004Fragrance Deionized water 0.286 Main Liquid Phase ¹Celatom FW14Diatomaceous Earth is a silicate with a typical 90% silica assay havingan average particle size of 8 μm. ²TEGO ® Foamex 810.

Example 3 Prophetic Example

A polishing composition is described in the table below.

Material Supplier Function CE-6040 Nanophase Nanoparticle TechnologiesAbrasive Duramul ZR 200/F¹ Washington Mills MicroparticleElectrominerals Base Abrasive Glycolic Acid Solution DuPont Organic Acid70 wt % Tech Solution Citric Acid Powder Jungbunzlauer Organic AcidAnhydrous USP Oxalic Acid Powder Samirian Organic Acid Sodium DodecylSulfate Pilot Chemical Surfactant (Calfoam SLS-30 Solution (30 wt %)) Di(Propylene Glycol) Dow Chemical Solvent Methyl Ether (Dowanol DPM)Defoamer² 0.003 Processing Aid BYK ® 420 .02 Thickener Fragrance 0.004Fragrance Deionized water 0.286 Main Liquid Phase ¹Duramul ZR 200/F is azirconia-mullite(aluminosilicate) grain produced by the electric furnaceand ground to a particle size wherein the largest particle is 75 μm witha typical average particle size of 30-40 μm ²TEGO ® Foamex 810 is adefoamer consisting of a proprietary mixture of modifiedpolyether-polysiloxane copolymer and fumed silica.

Example 4

A surface treatment composition, for producing a hydrophilic surface, isdescribed in the table below:

Nominal wt. Material Function fraction Supplier Bindzil ® CC 30 Silica0.0167 Eka Chemical (29.0 wt % Solids)* Nanoparticle Deionized waterSolvent 0.9757 N/A Aqua Ammonia pH 0.0076 Hydrite (19% solution)Adjustment Phenolphthalein pH Indicator 0.00004 Aldrich Chemical*Bindzil ® CC 30 is a nominal 29 wt % suspension of epoxy silanefunctionalized amorphous silica nanoparticles having a base particlesize of 7 nm.

Example 5

A surface treatment composition, for producing a hydrophilic surface, isdescribed in the table below:

Nominal wt. Material Function fraction Supplier Bindzil ® 830 Silica0.02 W. R. Grace (30.0 wt % Solids)¹ Nanoparticle Deionized waterSolvent 0.9222 N/A Aqua Ammonia pH Adjustment 0.0076 Hydrite (19%solution) TAMOL ® 1124² Surface wetting .00015 Rohm & Haas agentButoxyethanol Surface wetting 0.05 Aldrich (99.8% Solution) agentPhenolphthalein pH Indicator 0.00004 Aldrich Chemical ¹Ludox ® 830 is anominal 30 wt % suspension of amorphous silica nanoparticles having aspecific surface area of 200 m²/g. ²Tamol ® 1124 is a hydrophiliccopolymer dispersing agent.

Example 6

A surface treatment composition, for producing a hydrophilic surface, isdescribed in the table below:

Nominal wt. Material Function fraction Supplier Laponite ® RD*Nanoparticle 0.03 Southern Clay Products Deionized water Solvent 0.912N/A Ethanol Wetting Agent .05 ADM Aqua Ammonia pH Adjustment 0.0076Hydrite (19% solution) Phenolphthalein pH Indicator 0.00004 AldrichChemical *Laponite ® RD is a synthetic hectorite nanoclay thickener.This material has a tabular platelet structure with a typical diameterof 25 nm and a plate thickness of 1 nm.

Immediately following polishing with the polishing composition, thesurface is washed with clean water and allowed to dry. The surfacetreatment composition is then applied using a microfiber cloth to thepolished surface, to prepare a hydrophilic surface.

Application is best achieved by rubbing the surface treatmentcomposition on the polished surface in multiple passes and then making asingle final pass to level the resultant liquid. The liquid is thanallowed to dry for at least one hour to cure the treated surface.

A kit may also be provided, containing a polishing composition in afirst container, and a surface treating composition, in a secondcontainer. Preferably, the first and second containers are supplied in apackage, together.

1. (canceled)
 2. The heterocoagulate of claim 35, wherein the ceriumoxide is selected from the group consisting of ceria, mischmetal oxide,La/Ce oxides, zirconium-cerium oxides, mixed zirconium-rare earth oxidescontaining cerium, and mixtures thereof.
 3. The heterocoagulate of claim35, wherein the cerium oxide is ceria.
 4. The heterocoagulate of claim35, wherein the first particles have a particle size of 15 nm to 250 nm.5. The heterocoagulate of claim 35, wherein the first particles have anaverage particle size of 15 nm to 100 nm. 6-7. (canceled)
 8. Theheterocoagulate of claim 35, wherein the second particle has a particlesize of 3 to 250 microns.
 9. The heterocoagulate of claim 35, whereinthe second particle has an particle size of 10 to 100 microns. 10.(canceled)
 11. The intermediate of claim 37, wherein the cerium oxide isceria.
 12. The intermediate of claim 37, wherein the first particleshave an average particle size of 15 nm to 100 nm. 13-14. (canceled) 15.The intermediate of claim 37, wherein the second particles have aparticle size of 3 to 250 microns.
 16. The intermediate of claim 37,wherein the second particles have an average particle size of 3 to 100microns, and none of the second particles have a particle size greaterthan 100 microns.
 17. The intermediate of claim 37, wherein the firstparticles are present in an amount of 1 to 8% by weight.
 18. Theintermediate of claim 37, wherein the second particles are present in anamount of 30 to 60% by weight. 19-26. (canceled)
 27. The polishingcomposition of claim 37, wherein: the cerium oxide is ceria, the firstparticles have an average particle size of 15 nm to 100 nm, the secondparticles comprises an aluminosilicate, the second particles have anaverage particle size of 3 to 100 microns, none of the second particleshave a particle size greater than 100 microns, the first particles arepresent in an amount of 1 to 8% by weight, and the second particles arepresent in an amount of 30 to 60% by weight,
 28. A method of polishing asubstrate, comprising polishing the substrate with a compositioncomprising a plurality of heterocoagulates, each heterocoagulatecomprising (a) first particles, having a particle size of at most 999nm, on (b) a second particle, having a particle size of at least 1micron, wherein the particles comprise cerium oxide and silicon oxide,and the second particles are present in the composition in an amount of10 to 70% by weight.
 29. (canceled)
 30. The method of claim 28, whereinthe substrate is glass.
 31. The method of claim 29, wherein thesubstrate is a glass window having a mineral stain or deposit.
 32. Amethod of treating a surface of a substrate, comprising: polishing thesubstrate by the method of claim 30, to produce a polished surface ofthe substrate; and applying a surface treatment composition on thepolished surface, to produce a treated surface.
 33. The method of claim32, wherein the treated surface is hydrophilic.
 34. (canceled)
 35. Aheterocoagulate, comprising a plurality of first particles on thesurface of a second particle, wherein the particles comprisenanoparticles and a microparticle, and the particles comprise ceriumoxide and silicon oxide.
 36. The heterocoagulate of claim 35, whereinthe nanoparticles have a particle size of 10 to 100 nm, and themicroparticle has a particle size of 1 micron to 100 microns.
 37. Anintermediate for preparing a polishing composition, comprising: (1) aplurality of heterocoagulates, each heterocoagulate comprising (a) firstparticles, having a particle size of at most 999 nm, on (b) a secondparticle, having a particle size of at least 1 micron, and (2) water,wherein the particles comprise cerium oxide and silicon oxide, and thesecond particles are present in an amount of 10 to 70% by weight.